Orally administered film strip dosage forms have been recently developed for the pharmaceutical industry, and are currently used for the sale of several popular over-the-counter drug products, including Listerine® breath strips, Triaminic® thin strips (active agent=diphenhydramine HCl), and Sudafed PE™ quick dissolve strips (active ingredient=phenylephrine HCl). The absolute bioavailability of diphenhydramine when ingested orally is approximately 61%, and the time to maximum serum concentration is about 3-4 hours. Phenylephrine is subject to extensive presystemic metabolism in the gut wall, such that the absolute bioavailability of phenylephrine when ingested orally is approximately 40% relative to intravenous dosing, and peak plasma concentrations are achieved in about 1-2 hours.
In addition, several manufacturers have proposed formulations that could be used to deliver prescription drugs. The vast majority of these formulations are “mucoadhesive” formulations designed for adhesion of the dosage form to mucosal tissue in the mouth, and transmission of the drug from the dosage form through the mucosal tissue into the systemic circulation. As described in U.S. Pat. No. 6,750,921 to Kim et al., film-forming agents have been used to manufacture drug delivery formulations for percutaneous or transdermal application, but these necessarily involve an adhesive composition to retain the agent in situ long enough to cause sustained release of the active ingredient. Bioerodible films are described in Tapolsky et al., U.S. Pat. No. 5,800,832. The films have an adhesive layer and a non-adhesive backing layer and are intended to adhere to the mucosal surface. Biegajski et al., U.S. Pat. No. 5,700,478, describes a water-soluble pressure-sensitive mucoadhesive suitable for use in a mucosal-lined body cavity.
The purported advantage of these mucoadhesive films resides in their ability to bypass the gastrointestinal tract, and barriers in the gastrointestinal tract to drug absorption such as first pass metabolism and decomposition of the active ingredient in the stomach. An additional advantage for these dosage forms, when compared to tablets, capsules and other dosage forms that must be swallowed, is that some patient populations have difficulty swallowing, such as children and the elderly.
Until now the prior art has been focused principally on improving the delivery profile of a given pharmaceutical agent with this dosage form, by increasing its rate of dissolution or absorption, or bypassing metabolic processes that reduce the bioavailability of the drug. The prior art has not appreciated that an innovator's drug product, be it a tablet, capsule, or other oral dosage form, has already proven itself effective through rigorous clinical testing, and that the innovator's product may already provide the optimum bioavailability of pharmaceutical agent. What is needed is a film product that mimics the pharmacokinetics of an innovator's product, and that follows the same metabolic and bioabsorption pathways as the innovator's product, to ensure that the dosage form achieves the proven clinical efficacy of the innovator product.